Mantle is a male of a very-short stature. His body is small in size, but big in belly, with visible chest-hair. In comparison to his small body, his head is huge, and its shape resembles that of a Chinese Buddha statue's. Mantle's face has very slanted and baggy eyes, with elongated eyelids. His hair is black and he also spots a beard.
Mantle's clothing consists of a black, ragged, peasant tunic with a piece of rope acting as a belt.
Mantle is a cunning, submissive and devious man who is usually seen pandering to Magma's every whim. During the village games, he ties up Suika and lies to the Kingdom of Science that she is drowning in order to distract and disqualify Kohaku from the fights. It's shown that he is very loyal to Magma, trying to help him acquire the position of chief in any way possible, such as throwing rocks and potentially injuring Kinro who was having an edge over his boss.
He is seen attempting to attack Senku along with Magma and Carbo once the villagers suspect a coming storm is caused by a sorcerer, only to be interrupted by Gen.
Mantle later praises Magma for his might after the latter supposedly kills new sorcerer.
Hearing Senku's plan to rig the village games and wanting to assure a victory for Magma, Mantle follows after Suika and ties her up. He tells the Kingdom of Science followers that Suika is drowning and someone needs to save her. Although it was clear he was lying, Kohaku wanted to make sure Suika wasn't in danger. She proceeded to chase after Suika, even after much reluctance from Senku and the others.
Due to Mantle's plan, Kohaku was absent for her round in the Village games, resulting in her loss. Mantle was successful in his plan.
He attempts to throw rocks at Kinrou, but Chrome stops him, saying that since the game's judge is Jasper, Mantle has no chance of cheating his way out. Mantle is terrified to see Senku preparing various poisons, blades and arrows in order to stop Magma. He faces Chrome in the second round and throws the fight once Magma seees Kohaku arriving so the latter is disqualified.
Once the cotton candy machine is crafted as a part of the cellphone making process, Mantle enjoys the taste of the sweet along with the rest of the villagers.
When Homura appears, Mantle is shocked when she identifies him.
Mantle had the ability to catch up to Suika, who herself is pretty speedy. Mantle was able to have a balanced spar with Chrome in the village games. He eventually forfeited, but not because he was in a bad position or shape.
- His name is a reference to the Earth Mantle which is the Middle layer within the Earth interior.